1. Field of the Invention
The present invention relates to a mass spectrometer and a mass spectrometry method.
2. Background Art
Ion traps, which have high sensitivity characteristics, are widely used in mass spectrometers. Of such ion traps, linear ion traps comprising quadrupole rods are capable of high sensitivity analysis because the amount of ions that can be trapped internally at one time (the trap capacity) is greater than conventional 3D traps (approximately 1,000 to 10,000), and are widely used.
Patent Document 1 discloses a method of mass selectively ejecting ions in a direction orthogonal to quadrupole rods after the ions are accumulated in a linear ion trap. With this method, a trap capacity of approximately 100,000 is achieved.
Patent Document 2 discloses the mass selective ejection of ions in the axial direction of quadrupole rods using a fringing field that occurs at an exit end portion of the quadrupole rods after the ions are accumulated in a linear ion trap. With this method, a trap capacity of approximately 100,000 is achieved.
Patent Document 3 discloses the mass selective ejection of ions in the axial direction of quadrupole rods using an extraction field that is generated with a wire electrode after the ions are accumulated in a linear ion trap. With this method, a trap capacity of approximately 100,000 is achieved.
Patent Document 4 discloses mass selective ejection in the axial direction using a harmonic potential that is formed in the axial direction after ions are accumulated in a linear ion trap. With this method, a trap capacity of approximately 100,000 is achieved.
In Patent Document 5, the mass selective linear ion trap portions disclosed in Patent Document 1, Patent Document 2, and Patent Document 4 are coupled in tandem, rough mass dissociation is performed at a first stage linear ion trap, and high accuracy mass dissociation is performed at a second stage linear ion trap. There is disclosed a method of improving the trap capacity for ions by a digit or more by controlling these traps in coordination.
[Patent Document 1] U.S. Pat. No. 5,420,425
[Patent Document 2] U.S. Pat. No. 6,177,668
[Patent Document 3] U.S. Patent Publication No. 2007/0181804
[Patent Document 4] U.S. Pat. No. 5,783,824
[Patent Document 5] U.S. Pat. No. 7,348,554